Unfortunately, I am unaware of recovering your document if it has been overwritten. There is a program online called DOC Regenerator that claims to be able to recover Word documents, but its not free. You can take a look at the trial version here:http://utility.downloadatoz.com/abstradrome-doc-regenerator/

Do you have any backups of the file, like theres an option in word ot make backup copies of the file each time its saved or something like that, Check Tools > Options .I believe its .bak extension files.

If you ever encountered a scenario where your computer hanged when you were editing a document then theres rare chances where an .asd may still exist on your computer which may contain the information you had in the file before the computer hanged.

Im not sure if you can but I think System Restore might be worth checking also.

well....i cant say much, but once i had recovered a document this way...in the folder options, enable "show all files". if u r lucky enough, u may find a file named something like "~$filename.doc"...it may contain the data which was there prior to saving the original document.